In thermally assisted optical/magnetic data storage, information bits are recorded on a layer of a storage medium at elevated temperatures, and the heated area in the storage medium determines the data bit dimension. Heat assisted magnetic recording (HAMR) generally refers to the concept of locally heating a recording medium to reduce the coercivity of the recording medium so that the applied magnetic writing field can more easily direct the magnetization of the recording medium during the temporary magnetic softening of the recording medium caused by the heat source. For HAMR, a tightly confined, high power laser light spot is used to preheat a portion of the recording medium to substantially reduce the coercivity of the heated portion. Then the heated portion is subjected to a magnetic field that sets the direction of magnetization of the heated portion. In this manner the coercivity of the medium at ambient temperature can be much higher than the coercivity during recording, thereby enabling stability of the recorded bits at much higher storage densities and with much smaller bit cells. Heat assisted magnetic recording can be applied to any type of magnetic storage media, including tilted media, longitudinal media, perpendicular media and patterned media.
In HAMR disc drives, it is desirable to efficiently deliver the laser light to the recording head. Various light delivery schemes have been proposed which include a laser or optical fiber that moves with the slider, suspension, or actuator arm. However, mounting a laser on the slider, suspension, or the actuator arm requires additional electrical connections for the laser. Also, the electrical power dissipated by the laser will substantially heat the slider, which is undesirable for obtaining the best performance from the reader. The added mass of the laser on the slider (or suspension assembly) may also degrade the dynamic and shock performance of the suspension. Optical fiber adds cost and is typically stiff. Attaching a stiff fiber to the suspension or actuator arm complicates the design.
There is a need for a recording device that can provide localized heating of a recording medium without the need for optical fiber or additional connections on the slider, suspension, or actuator arm.